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CN111094414A - Foamed sheet comprising calcium carbonate, method for preparing same, and food container comprising same - Google Patents

Foamed sheet comprising calcium carbonate, method for preparing same, and food container comprising same Download PDF

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Publication number
CN111094414A
CN111094414A CN201880033009.9A CN201880033009A CN111094414A CN 111094414 A CN111094414 A CN 111094414A CN 201880033009 A CN201880033009 A CN 201880033009A CN 111094414 A CN111094414 A CN 111094414A
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CN
China
Prior art keywords
foamed sheet
food container
calcium carbonate
foamed
present
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201880033009.9A
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Chinese (zh)
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CN111094414B (en
Inventor
李光熙
咸镇洙
许娓
金宇镇
河相勳
崔钟汉
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Huvis Corp
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Huvis Corp
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Publication date
Priority claimed from KR1020180075719A external-priority patent/KR102160456B1/en
Priority claimed from KR1020180075718A external-priority patent/KR102160455B1/en
Priority claimed from KR1020180075717A external-priority patent/KR102160454B1/en
Application filed by Huvis Corp filed Critical Huvis Corp
Publication of CN111094414A publication Critical patent/CN111094414A/en
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Publication of CN111094414B publication Critical patent/CN111094414B/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/228—Forming foamed products
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/24—Acids; Salts thereof
    • C08K3/26—Carbonates; Bicarbonates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Wrappers (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)

Abstract

The present invention relates to a foamed sheet containing calcium carbonate, which has the advantages of excellent thermal conductivity, uniform sheet surface, and excellent thermoformability, and a method for producing the same, and a food container using the same.

Description

Foamed sheet comprising calcium carbonate, method for preparing same, and food container comprising same
Technical Field
The present invention relates to a foamed sheet comprising calcium carbonate, a method for preparing the same, and a food container comprising the same.
Background
Products used as general food containers are classified into foamed type and non-foamed type. A foamed product is obtained by mixing and extruding polystyrene and a foaming gas, and has advantages such as shape maintenance, heat insulation, and price advantage because the product can maintain a thick thickness. In contrast, such foamed products have the disadvantage that harmful substances are detected at high temperatures. A product in a film form prepared from polypropylene which is stable to heat is used as a non-foamed container, which has advantages of low rate of change of form at high temperature and no detection of harmful substances, but has disadvantages of high price and poor heat insulation effect.
A typical product most commonly used as a disposable heat-resistant container is a bowl-noodle container, and a polystyrene foam container has been used, but a harmful substance is detected at a high temperature, and a paper container is used instead, but the disposable heat-resistant container has a disadvantage of being expensive.
With the increasingly convenient life of modern society, the use amount of disposable articles increases, and with the increase based on one person one house type, the demand for take-out food and simple cooking products also gradually increases. Accordingly, the demand for food packaging containers has increased, and further, the consumer demand for new container materials that are safe without harmful substances and have functions based on different uses has also increased day by day. Therefore, it is necessary to develop a packaging container having beautiful appearance, convenience, safety, and environmental friendliness.
Disclosure of Invention
Technical problem
The present invention provides a foamed sheet comprising calcium carbonate, a method for preparing the same, and a food container comprising the same.
Technical scheme
The present invention provides a foamed sheet formed of a polyester resin containing 0.5 to 5% by weight of calcium carbonate, characterized in that,
per 100cm of foamed sheet2The thickness deviation per unit area is 15% or less,
the average size of the cells of the foamed sheet is 100 to 700 μm.
The present invention also provides a method for producing a foamed sheet, comprising the steps of,
comprises introducing polyester resin and calcium carbonate (CaCO) into an extruder3) And a step of preparing a foamed sheet by extrusion foaming,
the calcium carbonate is added in an amount of 0.5 to 5 wt%.
Further, the present invention provides a food container characterized in that,
comprises a foamed sheet containing polyester resin and calcium carbonate, wherein the calcium carbonate is contained in an amount of 0.5 to 5 wt%, has a melting point of 245 to 253 ℃,
the elongation of the foamed sheet is 325 to 450% at a surface temperature of 160 ℃ after contact or non-contact heating,
the food container satisfies the following mathematical formula 2,
mathematical formula 2: H/D is more than or equal to 0.4,
in the case of the mathematical formula 2,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 7cm to 15cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
Further, the present invention provides a food container characterized in that,
comprises a foamed sheet containing polyester resin and calcium carbonate, wherein the content of the calcium carbonate is 0.5 to 5 weight percent, the melting point of the foamed sheet is 252 to 260 ℃,
the elongation of the foamed sheet is 230 to 500% at a surface temperature of 160 ℃ after contact or non-contact heating,
the food container satisfies the following mathematical formula 3,
mathematical formula 3: H/D is more than or equal to 0.01 and less than or equal to 0.4,
in the case of the mathematical formula 3,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 1cm to 8cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
Advantageous effects
The foamed sheet of the present invention contains calcium carbonate in a predetermined content, and has the advantages of excellent thermal conductivity, uniform sheet surface, and excellent processability and thermoformability.
Drawings
Fig. 1 is a schematic view of a food container of the present invention.
Fig. 2 is a cross-sectional view of the food container of the present invention.
Fig. 3 is an image of a cross section of the foamed sheet of the present invention taken with a Scanning Electron Microscope (SEM) in experimental example 1.
Fig. 4 is an image of whether wrinkles are formed or not when the foamed sheet according to an embodiment is foamed, in which (a) part is an image of the foamed sheet of the preparation example and (b) part is an image of the foamed sheet of the comparative preparation example.
Fig. 5 is an image of a cross section of the foamed sheet of the present invention taken with a Scanning Electron Microscope (SEM) in experimental example 2.
Fig. 6 is an image of a cross section of the foamed sheet of the present invention taken with a Scanning Electron Microscope (SEM) in experimental example 4.
Detailed Description
In general, when a foamed sheet is thermoformed, the foamed sheet is heated at a temperature suitable for the forming, and the foamed sheet having a closed cell structure has an air layer inside, and it is difficult to transmit heat to the inside. Therefore, the foamed sheet has a low thermal conductivity and causes problems such as sheet tearing during molding and insufficient molding profile, and if the heating time is increased to improve moldability, the surface of the sheet is heated and the surface of the molded article is deteriorated.
Accordingly, in order to solve the above-described problems, an object of the present invention is to provide a foamed sheet formed of a polyester resin containing calcium carbonate, having a small cell size and a low density, and a method for producing the same.
The foamed sheet of the present invention is described in detail below.
The present invention provides a foamed sheet formed of a polyester resin containing 0.5 to 5% by weight of calcium carbonate, characterized in that the foamed sheet has a thickness per 100cm2The thickness deviation per unit area is 15% or less, and the average size of the cells of the foamed sheet is 100 to 700 μm.
Specifically, the foamed sheet of the present invention may comprise 0.5 to 5 weight percent calcium carbonate (CaCO)3). Specifically, the foamed sheet may include 1 to 5 weight percent, 1.5 to 4.5 weight percent, or 2 to 3.5 weight percent calcium carbonate (CaCO)3). For example, calcium carbonate (CaCO)3) May be amorphous in shape. As described above, the present invention contains calcium carbonateThe foamed sheet of the present invention has a uniform sheet surface and excellent thermoformability.
In one example, the average size of the cells of the foamed sheet may be 100 μm to 700. mu.m. Specifically, the average size of the fine pores of the above foamed sheet may be 150 to 650 μm, 150 to 350 μm, or 300 to 600 μm, and more specifically, the average size of the fine pores of the foamed sheet may be 200 to 350 μm, or 350 to 500 μm. The calcium carbonate is uniformly mixed in the polyester resin and foamed, so that the size of the fine pores as described above can be formed.
The thermal conductivity of the calcium carbonate may be 1.0kcal/mh ℃ to 3.0kcal/mh ℃. Specifically, the thermal conductivity of the calcium carbonate may be 1.2kcal/mh ℃ to 2.5kcal/mh ℃, 1.5kcal/mh ℃ to 2.2kcal/mh ℃, or 1.8kcal/mh ℃ to 2.0kcal/mh ℃. More specifically, the thermal conductivity of the calcium carbonate may be 1.5kcal/mh ℃ to 2.5kcal/mh ℃ or 1.8kcal/mh ℃ to 2.3kcal/mh ℃. The foamed sheet comprising the calcium carbonate as described above has excellent thermal conductivity, thus having a uniform surface, and has excellent thermoformability.
Also, the foamed sheet may have an average density of 100kg/m3To 500kg/m3. Specifically, the average density of the foamed sheet may be 100kg/m3To 450kg/m3、150kg/m3To 400kg/m3Or 150kg/m3To 300kg/m3More specifically, the average density of the foamed sheet may be 100kg/m3To 300kg/m3Or 150kg/m3To 250kg/m3. The calcium carbonate is uniformly mixed in the polyester resin and foamed, so that the density as described above can be formed. Therefore, as the cell density of the foamed sheet increases, the impact resistance is excellent.
In one example, the thickness of the foamed sheet of the present invention may be 0.5mm to 5.0 mm. Specifically, the thickness of the above foamed sheet may be 1.0mm to 5.0mm, 1.5mm to 4.0mm, or 2.0mm to 3.0mm, and more specifically, the thickness of the foamed sheet may be 1.0mm to 3.0mm, or 2.0mm to 3.5 mm.
The foamed sheet of the present invention has a unit area of 100cm2May be 15% orThe following. Specifically, the thickness deviation of the foamed sheet of the present invention may be 12% or less, 10% or less, 8% or less, or 7% or less. More specifically, the thickness deviation of the foamed sheet of the present invention may be 1% to 10% or 5% to 8%.
In the present invention, the polyester resin may be one or more selected from aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and an ethylene glycol component or hydroxycarboxylic acid. For example, the polyester resin may be one or more selected from the group consisting of Polyethylene Terephthalate (PET), polybutylene Terephthalate (PBT), polylactic acid (PLA), Polyglycolic acid (PGA), Polyethylene adipate (PEA), Polyhydroxyalkanoate (PHA), polytrimethylene Terephthalate (PTT), and Polyethylene naphthalate (PEN). Specifically, polyethylene terephthalate (PET) may be used in the present invention.
In one example, the melting point of the foamed sheet of the present invention may be 245 ℃ to 253 ℃. Specifically, the melting point of the foamed sheet may be 247 ℃ to 251.5 ℃, 248 ℃ to 253 ℃, or 249.5 ℃ to 252 ℃. More specifically, the melting point of the foamed sheet may be 248 ℃ to 251 ℃.
In another example, in the present invention, the elongation of the foamed sheet may be 325% to 450% when the surface temperature is 160 ℃ after the contact or non-contact heating. Specifically, the foamed sheet may have an elongation of 340% to 420%, 400% to 440%, or 350% to 430% when the foamed sheet is heated by contact or non-contact heating to a surface temperature of 160 ℃. More specifically, the foamed sheet may have an elongation of 345 to 355% when the foamed sheet is heated by contact or non-contact heating to have a surface temperature of 160 ℃.
The foamed sheet of the present invention comprises calcium carbonate and a polyester resin, has a melting point of 252 ℃ to 260 ℃, and can have an elongation of 230% to 500% when the surface temperature of the foamed sheet after contact or non-contact heating is 160 ℃.
In one example, the melting point of the foamed sheet of the present invention may be 252 ℃ to 260 ℃. Specifically, the melting point of the foamed sheet may be 252.5 ℃ to 258 ℃ or 253 ℃ to 256 ℃. More specifically, the melting point of the foamed sheet may be 253.5 ℃ to 255 ℃.
In another example, the foamed sheet of the present invention may have an elongation of 230% to 500% when the foamed sheet is heated to a surface temperature of 160 ℃ by contact or non-contact heating. Specifically, the elongation of the foamed sheet under the above conditions may be 240% to 400%, 260% to 350%, or 245% to 300%. More specifically, the elongation of the foamed sheet under the above conditions may be 240% to 300% or 250% to 280%.
The foamed sheet of the present invention comprises the calcium carbonate and the polyester resin as described above, and has excellent heat resistance. For example, the following mathematical formula 1 may be satisfied.
Mathematical formula 1: v is more than or equal to 50%1-V0|/V0×100≤300％，
In the above-mentioned numerical expression 2,
V0represents the volume (mm) of the foamed sheet before oven exposure at 200 ℃ for 30 seconds3)，
V1Represents the volume (mm) of the foamed sheet after oven exposure at 200 ℃ for 30 seconds3)。
Specifically, the rate of change in size before and after placing a sample of the above foamed sheet into a 200 ℃ oven and exposing for 30 seconds was measured. This is a measurement value of heat of the food container including the foamed sheet, and corresponds to an actual use environment. For example, the above volume may mean a product value of the length, width and thickness of the foamed sheet. For example, the size change rate according to the above mathematical formula 1 may range from 50% to 300%, 50% to 250%, 50% to 200%, 50% to 150%, 50% to 100%, 50% to 80%, 80% to 300%, 100% to 300%, 150% to 300%, 200% to 300%, 250% to 300%, 80% to 250%, or 100% to 200%. The value satisfying the above-mentioned range of formula 1 indicates that the foamed sheet of the present invention hardly undergoes a morphological change even when used in a high-temperature environment. As a result, the foamed sheet of the present invention was found to have excellent heat resistance.
The foamed sheet of the present invention may have Barrier (Barrier) properties, hydrophilization functions, or water-proofing functions, and the resin foamed sheet of the present invention may further include one or more functional additives selected from the group consisting of surfactants, hydrophilizing agents, heat stabilizers, water-proofing agents, cell size enlarging agents, infrared attenuating agents, plasticizers, fire-proofing chemicals, pigments, elastic polymers, extrusion aids, antioxidants, air discharge preventing agents, and ultraviolet absorbers. Specifically, the resin foamed sheet of the present invention may include a thickener, a heat stabilizer, and a foaming agent.
The thickener is not particularly limited, but pyromellitic dianhydride (PMDA), for example, can be used in the present invention.
The heat stabilizer may be an organic phosphorus compound or an inorganic phosphorus compound. For example, the above-mentioned organic or inorganic phosphorus compound may be phosphoric acid and organic esters thereof, phosphorous acid and organic esters thereof. For example, the heat stabilizer may be a commercially available one, and the heat stabilizer may be phosphoric acid, alkyl phosphate ester, or aryl phosphate ester. Specifically, the heat stabilizer in the present invention may be triphenyl phosphate, but is not limited thereto and may be used without limitation in the conventional range as long as the heat stability of the above resin foamed sheet can be improved.
As an example of the above blowing agent, there is N2、CO2And a physical blowing agent such as freon, butane, pentane, neopentane, hexane, isohexane, n-heptane, isoheptane, chloromethane, and specifically, butane can be used in the present invention.
The invention provides a method for producing a foamed sheet, which comprises introducing a polyester resin and calcium carbonate (CaCO) into an extruder3) And performing extrusion foaming to prepare a foamed sheet, wherein the calcium carbonate is added in an amount of 0.5 to 5 weight percent.
In one example, the calcium carbonate may be added in an amount of 0.5 to 5 wt%. Specifically, the calcium carbonate may be added in an amount of 1 wt%To 5 weight percent, 1.5 weight percent to 4.5 weight percent, or 2 weight percent to 3.5 weight percent. More specifically, the calcium carbonate may be added in an amount of 1.0 to 3.0 weight percent or 3.0 to 4.5 weight percent. For example, calcium carbonate (CaCO)3) May be amorphous in shape. For example, calcium carbonate may be fed to the extruder in the form of a master batch. By adding calcium carbonate in the above manner, a foamed sheet having a uniform sheet surface and excellent thermoformability can be produced. Further, the thermal conductivity of the foamed sheet obtained by uniformly distributing calcium carbonate in the polyester resin and extruding and foaming the resin is increased, whereby the problem that the foamed sheet is torn when the foamed sheet is molded can be solved. On the other hand, the above calcium carbonate (CaCO)3) May be inorganic ions other than calcium carbonate (CaCO)3) Titanium oxide (TiO) may be used in addition to the above2) Or Talc (Talc) and the like.
In one example, the calcium carbonate may have an average size of 1 μm to 5 μm. Specifically, the calcium carbonate may have an average size of 1.5 μm to 4 μm, 1.5 μm to 2.5 μm, or 3.5 μm to 4.5 μm. More specifically, the calcium carbonate may have an average size of 1.5 μm to 3.5 μm or 2 μm to 3 μm.
In one example, in the step of introducing the polyester resin into the extruder, the polyester resin may have a form of microspheres (pellet), microparticles (grain), beads (bead), chips (chip), or the like, and may be introduced into the extruder in a powder (powder) form in some cases.
The polyester resin may be one or more selected from aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and an ethylene glycol component or a hydroxycarboxylic acid. For example, the polyester resin may be one or more selected from the group consisting of Polyethylene Terephthalate (PET), polybutylene Terephthalate (PBT), polylactic acid (PLA), Polyglycolic acid (PGA), Polyethylene adipate (PEA), Polyhydroxyalkanoate (PHA), polytrimethylene Terephthalate (PTT), and Polyethylene naphthalate (PEN). Specifically, polyethylene terephthalate (PET) may be used in the present invention.
In one example, the method for producing a foamed sheet of the present invention can produce a foamed sheet having a melting point of 245 to 253 ℃. Specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having a melting point of 247 ℃ to 251.5 ℃, 248 ℃ to 253 ℃, or 249.5 ℃ to 252 ℃. More specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having a melting point of 248 ℃ to 251 ℃.
In another example, the foamed sheet of the present invention can be produced by a method of producing a foamed sheet having an elongation of 325% to 450% at a surface temperature of 160 ℃ after contact or non-contact heating. Specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having an elongation of 340% to 420%, 400% to 440%, or 350% to 430% at a surface temperature of 160 ℃ after contact or non-contact heating. More specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having an elongation of 345% to 355% at a surface temperature of 160 ℃ after contact or noncontact heating.
In another example, the method of producing a foamed sheet of the present invention can produce a foamed sheet having a melting point of 252 ℃ to 260 ℃. Specifically, the method for producing a foamed sheet can produce a foamed sheet having a melting point of 252.5 ℃ to 258 ℃ or 253 ℃ to 256 ℃. More specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having a melting point of 253.5 ℃ to 255 ℃.
In addition, the preparation method of the foamed sheet can prepare the foamed sheet with the elongation of 230 to 500 percent when the surface temperature is 160 ℃ after contact or non-contact heating. Specifically, the method for producing the foamed sheet may produce a foamed sheet having an elongation of 240% to 400%, 260% to 350%, or 245% to 300% at a surface temperature of 160 ℃ after contact or non-contact heating. More specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having an elongation of 240% to 300% or 250% to 280% at a surface temperature of 160 ℃ after contact or non-contact heating.
The method for producing a foamed sheet of the present invention can be carried out by feeding the polyester resin and calcium carbonate introduced into an extruder into the extruder, melting the mixture, and extruding and foaming the mixture to produce a foamed sheet. Specifically, a mixture of the polyester resin chips and calcium carbonate is melted and extruded for foaming. For example, the process of melting the polyester resin and the calcium carbonate may be performed at a temperature of 260 ℃ to 300 ℃.
In one example, the step of preparing the foamed sheet may include a foaming step of foaming a polyester resin containing calcium carbonate to prepare the foamed sheet. The foaming step can be carried out by using extruders of various forms. The foaming process is generally performed by bead foaming or extrusion foaming, preferably using extrusion foaming. In the extrusion foaming, generally, the resin melt is continuously extruded and foamed, so that the process steps can be simplified, mass production can be achieved, cracks, particle damage, and the like can be prevented from occurring between beads at the time of bead foaming, and excellent buckling strength and compressive strength can be realized.
The average size of the cells of the foamed sheet formed in the method of producing a foamed sheet of the present invention may be 100 to 700 μm. Specifically, the average size of the micro pores of the foamed sheet may be 100 to 600 μm, 100 to 500 μm, 100 to 400 μm, 100 to 300 μm, 150 to 650 μm, 150 to 350 μm, or 300 to 600 μm, and more specifically, the average size of the micro pores of the foamed sheet may be 200 to 350 μm, or 350 to 500 μm. The calcium carbonate is uniformly mixed in the polyester resin, so that the micropores having an average size as described above can be formed. Therefore, the foamed sheet has an increased average density and is excellent in impact resistance.
In the step of preparing the foamed sheet in the present invention, the thickness of the foamed sheet may be 0.5mm to 5.0 mm. Specifically, the thickness of the above foamed sheet may be 1.0mm to 5.0mm, 1.5mm to 4.0mm, or 2.0mm to 3.0mm, and more specifically, the thickness of the foamed sheet may be 1.0mm to 3.0mm, or 2.0mm to 3.5 mm.
The method for producing a foamed sheet of the present invention can produce a foamed sheet having an average thickness variation of 15% or less. Specifically, the method for producing a foamed sheet of the present invention can produce a foamed sheet having an average thickness variation of 12% or less, 10% or less, 8% or less, or 7% or less. More specifically, the method of producing a foamed sheet of the present invention can produce a foamed sheet having an average thickness deviation of 1% to 10% or 5% to 8%. For example, the method for producing the foamed sheet of the present invention can produce 100cm per unit area2Is 1% to 5.5% or 3% to 5%.
In one example, the foamed sheet of the present invention can be produced by a method of producing a foamed sheet having an average density of 100kg/m3To 500kg/m3The foamed sheet of (1). Specifically, the above method for producing a foamed sheet can produce a foamed sheet having an average density of 100kg/m3To 450kg/m3、150kg/m3To 400kg/m3Or 150kg/m3To 300kg/m3More specifically, the above-mentioned foamed sheet can be produced to have an average density of 100kg/m3To 300kg/m3Or 150kg/m3To 250kg/m3The foamed sheet of (1). The calcium carbonate is uniformly mixed in the polyester resin and foamed, so that the density as described above can be formed.
For example, in the step of preparing the foamed sheet of the present invention, additives in various forms may be added. The additives may be added in the fluid line or during the foaming process, as desired. The foamed layer of the present invention may have Barrier (Barrier) properties, hydrophilization functions, or water-repellent functions, and may contain, as an additive, one or more functional additives selected from thickeners, surfactants, hydrophilizing agents, heat stabilizers, water-proofing agents, pore size enlarging agents, infrared attenuating agents, plasticizers, fire-retardant chemicals, pigments, elastic polymers, extrusion aids, antioxidants, nucleating agents, air discharge preventing agents, and ultraviolet absorbers. Specifically, in the method for producing a foamed sheet of the present invention, one or more of a thickener, a nucleating agent, a heat stabilizer, and a foaming agent may be added, and one or more of the above-listed functional additives may be further included.
For example, in the step of preparing the foamed sheet of the present invention, one or more functional additives selected from the group consisting of a thickener, a hydrophilizing agent, a heat stabilizer, a water repellent, a pore size enlarging agent, an infrared ray attenuating agent, a plasticizer, a fire retardant chemical, a pigment, an elastic polymer, an extrusion aid, an antioxidant, a nucleating agent, an air discharge preventing agent, and an ultraviolet absorber may be put into the fluid connection line. Among additives required for preparing the foam, additives not introduced into the fluid connection line may be introduced into the extrusion process.
The above thickener is not particularly limited, but pyromellitic dianhydride (PMDA) can be used in the present invention.
The heat stabilizer may be an organic phosphorus compound or an inorganic phosphorus compound. For example, the above-mentioned organic or inorganic phosphorus compound may be phosphoric acid and organic esters thereof, phosphorous acid and organic esters thereof. For example, the heat stabilizer may be a commercially available one, and the heat stabilizer may be phosphoric acid, alkyl phosphate ester, or aryl phosphate ester. Specifically, the heat stabilizer in the present invention may be triphenyl phosphate, but is not limited thereto and may be used without limitation in the conventional range as long as the heat stability of the above resin foamed sheet can be improved.
Examples of the blowing agent include N2、CO2And a physical blowing agent such as freon, butane, pentane, neopentane, hexane, isohexane, n-heptane, isoheptane, chloromethane, and specifically, butane can be used in the present invention.
The water repellent is not particularly limited, and examples thereof include silicones, epoxies, cyanoacrylates, polyvinyl acrylates, vinyl acetates, acrylates, chlorobutadiene, mixtures of polyurethane resins and polyester resins, mixtures of polyols and polyurethane resins, mixtures of acrylic polymers and polyurethane resins, and mixtures of polyimides and mixtures of cyanoacrylates and urethanes.
Fig. 1 is a sectional view of a food container of the present invention. Referring to fig. 1, the food container of the present invention may have a circular or quadrangular shape in a pattern viewed from the upper side.
Also, the present invention may provide a food container including a foamed sheet formed of a polyester resin containing 0.5 to 5 weight percent of calcium carbonate.
More specifically, there is provided a food container wherein the above calcium carbonate is contained in an amount of 0.5 to 5% by weight, the melting point is 245 to 253 ℃, and the elongation of the foamed sheet is 325 to 450% at a surface temperature of 160 ℃ after contact or non-contact heating, satisfying the following numerical formula 2.
Mathematical formula 2: H/D is more than or equal to 0.4,
in the case of the mathematical formula 2,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 7cm to 15cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
The polyester resin may include repeating units induced by an acid component and a glycol component. Specifically, the polyester resin may be one or more selected from aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and an ethylene glycol component or a hydroxycarboxylic acid. For example, the polyester resin may be one or more selected from the group consisting of Polyethylene Terephthalate (PET), Polybutylene Terephthalate (PBT), polylactic acid (PLA), Polyglycolic acid (PGA), Polyethylene adipate (PEA), Polyhydroxyalkanoate (PHA), Polytrimethylene Terephthalate (PTT), and Polyethylene naphthalate (PEN). Specifically, Polyethylene Terephthalate (PET) may be used in the present invention.
For example, the content of the inorganic particles may be 0.5 to 5 weight percent. Specifically, the content of the inorganic particles may be 1 to 5 weight percent, 1.5 to 4.5 weight percent, or 2 to 3.5 weight percent. More specifically, the content of the inorganic particles may be 0.8 weight percent to 1.3 weight percent.
In one example, the food container of the present invention may have a melting point of 245 ℃ to 253 ℃. In particular, the melting point of the food container may be 247 ℃ to 251.5 ℃, 248 ℃ to 253 ℃, or 249.5 ℃ to 252 ℃. More specifically, the melting point of the food container may be 248 ℃ to 251 ℃.
In another example, in the foamed sheet for a food container of the present invention, the foamed sheet may have an elongation of 325% to 450% when the surface temperature is 160 ℃ after contact or non-contact heating. Specifically, the elongation percentage in the foamed sheet of the food container may be 340 to 420%, 400 to 440%, or 350 to 430% at a surface temperature of the foamed sheet after contact or non-contact heating of 160 ℃. More specifically, the foamed sheet of the food container may have an elongation of 345% to 355% at a surface temperature of 160 ℃ after contact or non-contact heating.
Fig. 1 is a sectional view of a food container of the present invention, and the food container of the present invention may have a circular or quadrangular shape as viewed from the upper side.
The food container of the present invention has excellent processability due to the inclusion of the polyester and calcium carbonate as described above. For example, the following mathematical formula 2 may be satisfied.
Mathematical formula 2: H/D is more than or equal to 0.4,
in the mathematical formula 2, the first and second groups,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 7cm to 15cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm. For example, in the above mathematical formula 2, the H/D value may be 0.4 to 1.0, 0.5 to 0.95, or 0.6 to 0.8. Specifically, in the above mathematical formula 2, the H value may be 7cm to 15cm, 8cm to 11cm, or 10cm to 14 cm. More specifically, in the above mathematical formula 2, the H value may be 9cm to 12 cm. Having the H/D value as described above means that the food container of the present invention is excellent in moldability and can be dip molded.
The ratio of the thickness of the side portion/the lower portion of the food container of the present invention (the thickness of the side surface/the thickness of the bottom surface) may be 0.8 or more. Specifically, the side/lower portion thickness ratio of the food container may be 0.85 or more, 0.9 or more, or 0.95 or more. More specifically, the side/lower portion thickness ratio of the food container may be 0.85 to 1.0 or 0.9 to 0.97. In this case, the thickness of the side surface is a value of the thickness of the side surface measured at the midpoint along the height direction of the food container, and the thickness of the bottom surface is a value of the thickness measured at the midpoint along the lateral and vertical directions of the bottom surface of the food container.
In one example, the food container of the present invention may have a compressive strength of 5kgf cm/cm2To 25kgf cm/cm2. Specifically, when the H/D value of the food container of the present invention is 0.6, the compressive strength may be 7kgf cm/cm2To 22kgf cm/cm2、8kgf·cm/cm2To 15kgf cm/cm2Or 12kgf cm/cm2To 20kgf cm/cm2. More specifically, the food container of the present invention may have a compressive strength of 10kgf cm/cm2To 15kgf cm/cm2. The food container of the present invention has excellent durability because of the compressive strength as described above.
Also, the present invention provides a food container comprising a foamed sheet comprising a polyester resin and calcium carbonate, wherein the calcium carbonate is contained in an amount of 0.5 to 5% by weight, the foamed sheet has a melting point of 252 to 260 ℃, and when the surface temperature is 160 ℃ after contact or non-contact heating, the foamed sheet has an elongation of 230 to 500%,
the food container satisfies the following mathematical formula 3,
mathematical formula 3: H/D is more than or equal to 0.01 and less than or equal to 0.4,
in the case of the mathematical formula 3,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 1cm to 8cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
Fig. 2 is a schematic view of a food container according to the present invention, wherein (a) is an image of the food container viewed from the upper end, and (b) is an image showing a side sectional view of the food container. In fig. 2, H represents the depth of the inside of the housing part, H is 1cm to 8cm, and D represents the length of the outside of the upper end of the housing part. When the food container is rectangular, D and D can be used1And D2The H/D value was calculated based on the average value of (2). The structure of the food container of the present invention will be described in detail below.
For example, in the above mathematical formula 3, the H/D value may be 0.01 to 0.37, 0.05 to 0.35, or 0.1 to 0.38. Specifically, in the above numerical formula 3, the H value may be 1.5cm to 7.0cm, 2.0cm to 5.0cm, or 4.0cm to 7.5 cm. More specifically, in the above mathematical formula 2 (whether or not is mathematical formula 3.
The food container comprises a bottom part and a wall part formed along the periphery of the bottom part with the upper end in an open state, wherein the average thickness of the bottom part and the average thickness of the wall part are respectively in the range of 0.8mm to 2.0mm, and the average thickness (T) of the bottom parta) And the average thickness (T) of the wallb) Ratio (T)a：Tb) The range may be 1: 0.80 to 1: 1.20. more specifically, the average thickness of the bottom portion and the average thickness of the wall portion may be 0.8mm to 2.0mm, 0.9mm to 1.8mm, 1.0mm to 1.6mm, 1.1mm to 1.4mm, or 1.2mm to 1.3mm, respectively. On the other hand, when the bottom portion 11 and the wall portion 12 of the food packaging container 10 are within the above ranges, the strength and rigidity can be prevented from being lowered while achieving weight reduction. And, the average thickness (T) of the bottom parta) And the average thickness (T) of the wallb) Ratio (T)a：Tb) The range may be 1: 0.95 to 1: 1.05. in one example, the average thickness (T) of the bottom portiona) And the average thickness (T) of the wallb) Ratio (T)a：Tb) The range may be 1: 0.95 to 1: 1.0 or 1: 0.97 to 1: 0.99.
in this case, the thickness of the side surface is a value of the thickness of the side surface measured at the midpoint along the height direction of the food container, and the thickness of the bottom surface is a value of the thickness measured at the midpoint along the lateral and vertical directions of the bottom surface of the food container.
In one example, the food container of the present invention may have a compressive strength of 11kgf cm/cm2To 40kgf cm/cm2. Specifically, when the H/D value of the food container of the present invention is 0.4, the compressive strength may be 17kgf cm/cm2To 22kgf cm/cm2Or 18kgf cm/cm2To 23kgf cm/cm2. More specifically, the food container of the present invention may have a compressive strength of 19kgf cm/cm2To 21kgf cm/cm2. The food container of the present invention has excellent durability because of the compressive strength as described above.
In another example, the food container of the present invention may satisfy the following equation 4.
Mathematical formula 4: i V3-V2|/V2×100≤10％，
In the above-mentioned mathematical formula 4,
V2represents the volume (mm) of the container before the exposure of the microwave oven for 5 minutes at 1kw3)，
V3Represents the volume (mm) of the container after 5 minutes of exposure in a 1kw microwave oven3)。
Specifically, the size change rate before and after placing a sample of the above foamed sheet in a 1kw microwave oven and exposing for 5 minutes was measured. This is a measured value of the heat of the food container including the foamed sheet, and corresponds to an actual use environment. For example, the volume may mean a product of the length, width, and thickness of the container opening. For example, the size change rate according to the above mathematical formula 4 may range from 0.01% to 10%, 0.01% to 8%, 0.01% to 6%, 0.01% to 4%, 0.01% to 2%, 0.01% to 1%, 1% to 10%, 2% to 10%, 4% to 10%, 6% to 10%, or 8% to 10%. The value satisfying the above-mentioned numerical expression 4 indicates that the food container of the present invention hardly undergoes morphological changes even when used in a high-temperature environment. As a result, the food container of the present invention was found to have excellent heat resistance.
The present invention will be described in more detail below with reference to examples and experimental examples.
However, the following examples and experimental examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.
Preparation example 1
1 weight percent of calcium carbonate and polyethylene terephthalate (PET) resin were mixed, 0.5 weight parts of pyromellitic dianhydride and 0.1 weight parts of Irganox (IRG 1010) were mixed based on 100 weight parts of polyethylene terephthalate (PET) resin, and the mixture was heated at 280 ℃ to prepare a resin melt. Thereafter, butane was added to the first extruder as a foaming agent, and 1 part by weight of butane was added based on 100 parts by weight of polyethylene terephthalate (PET) resin and extrusion foaming was performed, thereby preparing a foamed sheet of polyethylene terephthalate (PET) resin having a thickness of 2 mm.
Preparation example 2
Except that 1.5 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 1.
Preparation example 3
Except that 3.0 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 1.
Preparation example 4
Except that 4.5 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 1.
Comparative preparation example 1
Except that 5.3 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 4.
Comparative preparation example 2
A foamed sheet was produced in the same manner as in production example 1, except that 0.6 weight percent of Talc (Talc) was added.
Comparative preparation example 3
A foamed sheet was produced in the same manner as in production example 1, except that 1.0 weight percent of Talc (Talc) was added.
Example 1
The foamed sheet prepared in preparation example 1 was passed through an IR type ceramic Heater (Heater) zone, the temperature of the upper Heater (Heater) was set to 400 ℃, the temperature of the lower Heater (Heater) was set to 280 ℃, and the dead time was set to 30 seconds so that the surface temperature of the foamed sheet became 160 ℃, and then, the foamed sheet was compressed (Press) with a Mold temperature Plug (Plug) of 60 ℃ and a Mold (Mold) of 120 ℃ for 7 seconds, thereby preparing a food container.
At this time, a quadrangular food container having an H/D of 0.38, a height (H) of 5cm and an upper end length of 13cm was prepared.
Example 2
A food container was prepared under the same conditions as in example 1, except that the foamed sheet prepared in preparation example 2 was used.
Example 3
A food container was prepared under the same conditions as in example 2, except that the mold was compressed for 8 seconds.
Example 4
A food container was prepared under the same conditions as in example 1, except that the foamed sheet prepared in preparation example 3 was compressed for 6 seconds using a mold.
Example 5
A food container was prepared under the same conditions as in example 4, except that the foamed sheet prepared in preparation example 4 was used.
Comparative example 1
A food container was prepared under the same conditions as in example 4, except that the foamed sheet prepared in comparative preparation example 1 was used.
Comparative example 2
A food container was prepared under the same conditions as in example 3, except that the foamed sheet prepared in comparative preparation example 2 was used.
Comparative example 3
A food container was prepared under the same conditions as in comparative example 2, except that the foamed sheet prepared in comparative preparation example 3 was used and compressed with a mold for 10 seconds.
Experimental example 1
In order to confirm the physical properties of the foamed sheets of the present invention, thickness variations were measured for the foamed sheets of production examples 1 to 4 and comparative production examples 1 to 3, and moldability experiments were performed for the food containers produced in examples 1 to 5 and comparative examples 1 to 3, and the results thereof are shown in table 1. A cross section of the foamed sheet of preparation example 1 was photographed by a Scanning Electron Microscope (SEM), and the result thereof is shown in fig. 3.
At this time, in the moldability test, the temperature of the upper heater was 400 ℃, the temperature of the lower heater was 320 ℃, when the surface temperature of the foamed sheet was 155 ℃ to 160 ℃, molding was performed at a temperature of 80 ℃ by a mold, and the degree of molding of the foamed sheet was observed.
TABLE 1
Figure GDA0002422376140000151
Figure GDA0002422376140000161
As can be seen from table 1, the foamed sheets of production examples 1 to 4 had a thickness variation of 10% or less and a uniform surface. In contrast, the calcium carbonate in comparative preparation example 1 was added in an amount of 5.3 wt%, contained a large amount of calcium carbonate, and wrinkles occurred after passing through the extrusion press in the foaming step and had a thickness variation of 15% or more (specifically, 18%). In comparative production examples 2 and 3, the foamed sheets containing talc had a thickness variation of 10% or more, and in comparative production example 3, the foamed sheets had a thickness variation of 20%, had a non-uniform surface, and had wrinkles and a large thickness variation after passing through an extrusion die in the foaming step, as compared with production example 1 containing the same amount of calcium carbonate.
Further, the foamed sheet of the present invention was molded to prepare a food container, and a moldability test was performed, and as a result, it was confirmed that the moldability of examples 1 to 5 was excellent as a whole. Specifically, the fine profiles of examples 2 to 5 were excellent and no wrinkles occurred. Also, examples 3 to 5 are excellent in moldability under low temperature conditions due to the influence of calcium carbonate. On the contrary, regarding the moldability of comparative example 1, the fine profile was good but wrinkles occurred due to the influence of calcium carbonate in the foaming process.
Referring to fig. 3, it can be seen that the microcellular generation uniformity of the foamed sheet of example 1 was uniform. Specifically, the average size of the cells of the foamed sheet of example 1 was 350 μm to 500 μm.
As can be seen from table 1 and fig. 4, the foamed sheets of production examples 1 to 4 did not wrinkle or fine wrinkles after passing through the extrusion die in the foaming step in the production process, whereas the foamed sheets of comparative examples 1 and 3 did wrinkle 20 to 24 times after passing through the extrusion die in the foaming step. Specifically, part (a) of fig. 4 is an image of the foamed sheet of production example 1, and part (b) is an image of the foamed sheet of comparative production example 1.
From this, it is understood that the foamed sheet of the present invention contains a predetermined amount of calcium carbonate, does not cause wrinkles in the production process of the foamed sheet, has a uniform thickness, and is excellent in moldability during molding.
Preparation example 5
1.0 weight percent of calcium carbonate and polyethylene terephthalate resin with a melting point of 249 ℃ are mixed, 0.5 weight part of pyromellitic dianhydride and 0.1 weight part of Irganox (IRG 1010) are mixed based on 100 weight parts of polyethylene terephthalate resin, and the mixture is heated at 280 ℃ to prepare a resin melt. Thereafter, butane was added to the first extruder as a foaming agent, 3 parts by weight of butane was added based on 100 parts by weight of polyethylene terephthalate (PET) resin, and extrusion foaming was performed, thereby preparing a foamed sheet of polyethylene terephthalate resin having a thickness of 2 mm.
Preparation example 6
Except that 3.0 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 5.
Comparative preparation example 4
A foamed sheet was produced in the same manner as in production example 5, except that a polyester resin having a melting point of 254 ℃.
Comparative preparation example 5
A foamed sheet was produced in the same manner as in production example 5, except that 1.0 weight percent of Talc (Talc) was added.
Example 6
The foamed sheet prepared in preparation example 5 was passed through an IR type ceramic Heater (Heater) zone, the temperature of the upper Heater (Heater) was set to 380 ℃, the temperature of the lower Heater (Heater) was set to 260 ℃, and the dead time was set to 24 seconds so that the surface temperature of the foamed sheet became 160 ℃, and then, the foamed sheet was compressed (Press) with a Mold temperature Plug (Plug) of 60 ℃ and a Mold (Mold) of 120 ℃ for 10 seconds, thereby preparing a container.
At this time, a circular food container having an H/D of 0.59, a height (H) of 8.5cm and an upper end length of 14.5cm was prepared.
Example 7
A food container was prepared under the same conditions as in example 6, except that the foamed sheet prepared in preparation example 6 was used.
Comparative example 4
A food container was prepared under the same conditions as in example 6, except that the foamed sheet prepared in comparative preparation example 4 was used.
Comparative example 5
A food container was prepared under the same conditions as in example 6, except that the foamed sheet prepared in comparative preparation example 5 was used.
Experimental example 2
In order to confirm the physical properties of the foamed sheet and the food container of the present invention, the foamed sheets of production examples 5 and 6 were measured for thickness variation, melting point, and high-temperature elongation, and the food containers of example 6 and 7 were measured for moldability and compressive strength, and the results are shown in table 2. A cross section of the foamed sheet of preparation example 5 was photographed by a Scanning Electron Microscope (SEM), and the result thereof is shown in fig. 5.
At this time, in the process of measuring the high-temperature elongation, the tensile strength tester was placed in an oven, and the test piece was held at an oven temperature of 200 ℃ for 30 seconds at a test speed of 50mm/min and a gap size of 20mm, with a height of 70mm × a width of 25 mm.
TABLE 2
Figure GDA0002422376140000181
Referring to table 2, it is apparent that the foamed sheets of the present invention have a uniform thickness and a uniform surface when the deviation in thickness of the foamed sheets of preparation examples 5 and 6 is less than 5% and the foamed sheets of comparative preparation examples 4 and 5 are 6% or more. Further, the foamed sheets of the present invention had a high-temperature elongation of 350% or more, and the foamed sheets of comparative preparation examples 4 and 5 had a high-temperature elongation of 280% or less, and it was found that the foamed sheets of the present invention had excellent high-temperature elongation. From this, it was confirmed that the foamed sheet of the present invention is excellent in moldability and favorable for dip molding, and the surface of the foamed sheet is uniform. As can be seen from fig. 5, the uniformity of cell formation was uniform in the foamed sheet of example 5.
Experimental example 3
In order to confirm the physical properties of the food containers of the present invention, the thickness ratio of the side portion/the bottom portion, the heat resistance, and the compressive strength were measured for the food containers of example 6, example 7, comparative example 4, and comparative example 5, and the results are shown in table 3.
At this time, the thickness of the right center of the side surface and the bottom surface was measured, and the ratio of the thickness of the side surface to the thickness of the bottom surface (lower portion) was used to indicate the ratio of the thickness of the side portion to the thickness of the lower portion.
In the measurement of heat resistance, water at 80 ℃ was added to a food container, and the container was heated in a 1kw microwave oven for 2 minutes and then measured, where O indicates no deformation by visual inspection and X indicates morphological deformation.
When the compressive strength was measured, the bottom surface of the food container was faced backward by a tensile strength tester, and the maximum load when the food container was compressed at a test speed of 50mm/min was measured.
TABLE 3
Figure GDA0002422376140000191
Referring to table 3, it can be seen that the thickness ratio of the side portion/lower portion in examples 6 and 7 was 0.85 or more, that is, the side and bottom portions were similar in thickness, whereas the thickness ratio of the side portion/lower portion could not be measured due to breakage during dip molding in comparative example 4, and the bottom portion was slightly larger than the side portion in comparative example 5, as compared to the food container of the present invention. Further, the samples of examples 6 and 7 were not changed in shape when heated in a 1kw microwave oven, and thus were excellent in heat resistance. The compression strengths of examples 6 and 7 were 11kgf cm/cm2Or more, it has superior strength compared to comparative example 5 containing talc. From these results, it is found that the food container comprising the foamed sheet of the present invention has an H/D value of 0.4 or more and excellent compressive strength.
Preparation example 7
1.0 weight percent of calcium carbonate and polyethylene terephthalate resin with a melting point of 254 ℃ are mixed, 0.5 weight part of pyromellitic dianhydride and 0.1 weight part of Irganox (IRG 1010) are mixed based on 100 weight parts of polyethylene terephthalate resin, and the mixture is heated at a temperature of 280 ℃ to prepare a resin melt. Thereafter, butane was added to the first extruder as a foaming agent, 3 parts by weight of butane was added based on 100 parts by weight of polyethylene terephthalate (PET) resin, and extrusion foaming was performed, thereby preparing a foamed sheet of polyethylene terephthalate resin having a thickness of 2 mm.
Preparation example 8
Except that 3.0 weight percent calcium carbonate (CaCO) was added3) Except that, a foamed sheet was prepared in the same manner as in preparation example 7.
Comparative preparation example 6
A foamed sheet was produced in the same manner as in production example 7, except that 0.6 weight percent of Talc (Talc) was added.
Comparative preparation example 7
A foamed sheet was produced in the same manner as in production example 7, except that 1.0 weight percent of Talc (Talc) was added.
Example 8
The foamed sheet prepared in preparation example 7 was passed through an IR type ceramic Heater (Heater) zone, the temperature of the upper Heater (Heater) was set to 400 ℃, the temperature of the lower Heater (Heater) was set to 280 ℃, and the dead time was set to 30 seconds so that the surface temperature of the foamed sheet became 160 ℃, and then, the foamed sheet was compressed (Press) with a Mold temperature Plug (Plug) of 60 ℃ and a Mold (Mold) of 120 ℃ for 10 seconds, thereby preparing a container.
At this time, a quadrangular food container having an H/D of 0.38, a height (H) of 5cm and an upper end length of 13cm was prepared.
Example 9
A food container was prepared under the same conditions as in example 8, except that the foamed sheet prepared in preparation example 8 was used.
Comparative example 6
A food container was prepared under the same conditions as in example 8, except that the foamed sheet prepared in comparative preparation example 6 was used.
Comparative example 7
A food container was prepared under the same conditions as in example 8, except that the foamed sheet prepared in comparative preparation example 7 was used.
Experimental example 4
In order to confirm the physical properties of the foamed sheet and the food container of the present invention, the foamed sheets of production examples 7 and 8 were measured for thickness variation, melting point, and high-temperature elongation, and the food containers of example 8 and 9 were measured for moldability and compressive strength, and the results are shown in table 4. Then, a cross section of the foamed sheet of preparation example 7 was photographed by a Scanning Electron Microscope (SEM), and the result thereof is shown in fig. 6.
At this time, in the process of measuring the high-temperature elongation, the tensile strength tester was placed in an oven, and the test piece was held at an oven temperature of 200 ℃ for 30 seconds at a test speed of 50mm/min and a gap size of 20mm, with a height of 70mm × a width of 25 mm.
TABLE 4
Figure GDA0002422376140000211
Referring to table 4, it is apparent that the foamed sheets of the present invention have a uniform thickness and a uniform surface when the deviation in thickness of the foamed sheets of preparation examples 7 and 8 is 10% or less and the foamed sheets of comparative preparation examples 6 and 7 is 10% or more. Further, the foamed sheets of production examples 7 and 8 had a high-temperature elongation of 250% or more, and the foamed sheets of comparative production examples 6 and 7 had a high-temperature elongation of 220% or less, and it was found that the foamed sheets of the present invention were excellent in high-temperature elongation. As can be seen from fig. 6, the uniformity of cell formation was uniform in the foamed sheet of example 8.
Experimental example 5
In order to confirm the physical properties of the food containers of the present invention, the thickness ratio of the side portion to the bottom portion, the heat resistance, and the compressive strength were measured for the food containers of example 8, example 9, comparative example 6, and comparative example 7, and the results are shown in table 5.
At this time, the thickness of the right center of the side surface and the bottom surface was measured, and the ratio of the thickness of the side surface to the thickness of the bottom surface (lower portion) was used to indicate the ratio of the thickness of the side portion to the thickness of the lower portion.
In the measurement of heat resistance, water at 80 ℃ was added to a food container, and the container was heated in a 1kw microwave oven for 2 minutes and then measured, where O indicates no deformation by visual inspection and X indicates morphological deformation.
When the compressive strength was measured, the bottom surface of the food container was faced backward by a tensile strength tester, and the maximum load when the food container was compressed at a test speed of 50mm/min was measured.
TABLE 5
Figure GDA0002422376140000221
As can be seen from table 5, the thickness ratio of the side portion/lower portion in examples 8 and 9 was 0.9 or more, that is, the side surface and the bottom surface were similar in thickness, whereas comparative examples 6 and 7 were less than 0.8, and the bottom surface was slightly thicker than the side surface. Further, when heated in a 1kw microwave oven, the samples of example 8 and example 9 were free from morphological changes, and were found to be excellent in heat resistance. Compressive strength of examples 8 and 9Is 15kgf cm/cm2Or more, superior strength compared to the comparative example containing talc.
Industrial applicability
The foamed sheet of the present invention contains calcium carbonate in a predetermined content, and has the advantages of excellent thermal conductivity, uniform sheet surface, and excellent processability and thermoformability.

Claims (15)

1. A foamed sheet formed of a polyester resin containing 0.5 to 5 weight percent of calcium carbonate,
per 100cm of foamed sheet2The thickness deviation per unit area is 15% or less,
the average size of the cells of the foamed sheet is 100 to 700 μm.
2. The foamed sheet according to claim 1, wherein the foamed sheet has an average thickness of 0.5mm to 5 mm.
3. The foamed sheet according to claim 1, wherein the foamed sheet has an average density of 100kg/m3To 500kg/m3。
4. The foamed sheet according to claim 1, wherein the polyester resin is one or more selected from aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and an ethylene glycol component or a hydroxycarboxylic acid.
5. The foamed sheet according to claim 1, wherein the foamed sheet has an average melting point of 245 to 253 ℃ and an elongation of 325 to 450% at a surface temperature of 110 ℃ after contact or noncontact heating.
6. The foamed sheet according to claim 1, wherein the foamed sheet has a melting point of 252 ℃ to 210 ℃ and an elongation of 230% to 500% at a surface temperature of 110 ℃ after contact or non-contact heating.
7. The foamed sheet according to claim 1, wherein the foamed sheet satisfies the following numerical formula 1,
mathematical formula 1: v is more than or equal to 50%1-V0|/V0×100≤300％，
In the above-mentioned mathematical formula 1,
V0represents the volume (mm) of the foamed sheet before oven exposure at 200 ℃ for 30 seconds3)，
V1Represents the volume (mm) of the foamed sheet after oven exposure at 200 ℃ for 30 seconds3)。
8. A method for preparing a foamed sheet is characterized in that,
comprising the steps of introducing a polyester resin and calcium carbonate into an extruder and extruding and foaming the mixture to prepare a foamed sheet,
the calcium carbonate is added in an amount of 0.5 to 5 wt%.
9. The method of claim 8, wherein the foamed sheet has an average size of micropores of 100 to 700 μm.
10. A food container, characterized in that,
comprises a foamed sheet containing polyester resin and calcium carbonate, wherein the calcium carbonate is contained in an amount of 0.5 to 5 wt%, has a melting point of 245 to 253 ℃,
the elongation of the foamed sheet is 325 to 450% at a surface temperature of 110 ℃ after contact or non-contact heating,
the food container satisfies the following mathematical formula 2,
mathematical formula 2: H/D is more than or equal to 0.4,
in the above-mentioned numerical expression 2,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 7cm to 15cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
11. The food container according to claim 10, wherein the compression strength is 5 kgf-cm/cm2To 25kgf cm/cm2。
12. A food container, characterized in that,
comprises a foamed sheet containing polyester resin and calcium carbonate, wherein the content of the calcium carbonate is 0.5 to 5 weight percent, the melting point of the foamed sheet is 252 to 210 ℃,
the elongation of the foamed sheet is 230 to 500% at a surface temperature of 110 ℃ after contact or non-contact heating,
the food container satisfies the following mathematical formula 3,
mathematical formula 3: H/D is more than or equal to 0.01 and less than or equal to 0.4,
in the above-mentioned numerical expression 3,
a food container including a receiving portion is formed,
h represents the depth of the outer side of the receiving part, H is 1cm to 8cm,
d represents the length of the outer side of the upper end of the containing part, and the unit is cm.
13. Food product container according to claim 12,
the food container comprises a bottom and a wall part formed along the periphery of the bottom and having an open upper end,
the average thickness of the bottom and the average thickness of the wall are respectively in the range of 0.8mm to 2.0mm,
average thickness (T) of the bottoma) And the average thickness (T) of the wallb) Ratio (T)a：Tb) The range is 1: 0.80 to 1: 1.20.
14. the food container according to claim 12, wherein the compression strength is 11 kgf-cm/cm2To 40kgf cm/cm2。
15. The food container according to claim 12, wherein the food container satisfies the following numerical formula 4,
mathematical formula 4: i V3-V2|/V2×100≤10％
In the above-mentioned numerical formula 4,
V2represents the volume (mm) of the container before the exposure of the microwave oven for 5 minutes at 1kw3)，
V3Represents the volume (mm) of the container after 5 minutes of exposure in a 1kw microwave oven3)。
CN201880033009.9A 2018-06-29 2018-12-26 Foamed sheet comprising calcium carbonate, method for producing the same, and food container comprising the same Active CN111094414B (en)

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KR1020180075718A KR102160455B1 (en) 2018-06-29 2018-06-29 Foam sheet having an excellent workability, preparation method thereof, and food container comprising the same
KR10-2018-0075718 2018-06-29
KR1020180075717A KR102160454B1 (en) 2018-06-29 2018-06-29 Excellent heat resistance foam sheet, preparation method thereof, and food container comprising the same
PCT/KR2018/016676 WO2020004748A1 (en) 2018-06-29 2018-12-26 Foamed sheet comprising calcium carbonate, manufacturing method therefor, and food container comprising same

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112166143A (en) * 2019-04-25 2021-01-01 株式会社 Huvis Foamed sheet containing inorganic particles and method for producing same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5000991A (en) * 1988-12-01 1991-03-19 Sekisui Kaseihin Kogyo Kabushiki Kaisha Process for producing polyester resin foam and polyester resin foam sheet
JPH10180952A (en) * 1996-12-25 1998-07-07 Sekisui Plastics Co Ltd Heat-resistant food container
JP2003026845A (en) * 2001-07-11 2003-01-29 Kanegafuchi Chem Ind Co Ltd Foaming polyester resin composition
CN104817830A (en) * 2015-05-15 2015-08-05 北京化工大学 Aromatic polyester foaming microcellular foaming material and preparation method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4221279B2 (en) * 2003-11-26 2009-02-12 住友ゴム工業株式会社 Resin foam manufacturing method and paper sheet multi-feed preventing member using the foam
EP1944333A4 (en) * 2005-11-04 2009-12-02 Unitika Ltd Biodegradable resin foam sheet, biodegradable resin foam article and biodegradable resin molded container
US20150099112A1 (en) * 2012-12-21 2015-04-09 Nitto Denko Corporation Resin foam and foam sealing material
KR101887918B1 (en) * 2016-09-30 2018-08-13 주식회사 휴비스 Food Container Improved Heat-blocking Ability

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5000991A (en) * 1988-12-01 1991-03-19 Sekisui Kaseihin Kogyo Kabushiki Kaisha Process for producing polyester resin foam and polyester resin foam sheet
US5000991B1 (en) * 1988-12-01 1997-09-16 Sekisui Plastics Process for producing polyester resin foam and polyester resin foam sheet
US5000991B2 (en) * 1988-12-01 2000-07-11 Sekisui Plastics Process for producing polyester resin foam and polyester resin foam sheet
JPH10180952A (en) * 1996-12-25 1998-07-07 Sekisui Plastics Co Ltd Heat-resistant food container
JP2003026845A (en) * 2001-07-11 2003-01-29 Kanegafuchi Chem Ind Co Ltd Foaming polyester resin composition
CN104817830A (en) * 2015-05-15 2015-08-05 北京化工大学 Aromatic polyester foaming microcellular foaming material and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
[加]GEORGE WYPYCH编著: "《填料手册（第二版）》", 31 October 2002, 中国石化出版社 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112166143A (en) * 2019-04-25 2021-01-01 株式会社 Huvis Foamed sheet containing inorganic particles and method for producing same
CN112166143B (en) * 2019-04-25 2023-07-07 株式会社 Huvis Foamed sheet containing inorganic particles and method for producing same

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